Field of the Invention
The invention relates to a method, a radio communications system and a mobile station for information transmission. The invention pertains, in particular, to radio communications systems in which information is transmitted by means of radio blocks in accordance with a time pattern.
Information (for example voice, video information or other data) is transmitted in radio communications systems by means of electromagnetic waves via a radio interface between a transmitting and a receiving radio station (base station and mobile station). The electromagnetic waves are in this case transmitted at carrier frequencies which are in the frequency band intended for the respective system. Frequencies in the frequency band around 2000 MHz are intended for future mobile radio networks using CDMA or TD/CDMA transmission methods via the radio interface, for example the UMTS (Universal Mobile Telecommunication System) or other 3rd generation systems. Methods which are known as frequency division multiple access (FDMA), time division multiple access (TDMA) and/or a method known as code division multiple access (CDMA) can be used to distinguish between different signal sources in the receiver.
One particular version of time division multiple access (TDMA) is a TDD (time division duplex) transmission method, in which the transmission takes place both in the uplink direction, that is to say from the mobile station to the base station, and in the downlink direction, that is to say from the base station to the mobile station, using a common frequency channel.
It has become known from German published patent application DE 197 13 667 for both user information and organization information to be transmitted in one timeslot. A mobile station which has been assigned such a timeslot for user information can evaluate the organization information from the same radio cell at the same time. The mobile station is thus not free to evaluate the organization information items for adjacent cells, which are normally transmitted in a defined timeslot. One alternative is known from the GSM mobile radio network. In this case, a dedicated timeslot is reserved only for the organization information, so that a mobile station can decide from frame to frame the base station from which it receives the organization information. The user information is transmitted in other timeslots, which do not change. The position of the information transmission within the time pattern does not change in either case.
U.S. Pat. No. 5,020,056 describes a mobile radio system in which a change of timeslots for the individual connections is carried out in order to reduce synchronous fading. In this way, the interval between the transmitted radio blocks varies from frame to frame for each connection in accordance with a specific sequence.
European published patent application EP 0 720 321 describes a mobile radio system which operates using a TDD method.
U.S. Pat. No. 5,493,563 describes a mobile radio system which operates using a TDMA method. A frequency hopping method is used to assist connection handover.